9991023 has 8 divisors (see below), whose sum is σ = 15224448. Its totient is φ = 5709144.

The previous prime is 9990997. The next prime is 9991027. The reversal of 9991023 is 3201999.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 9991023 - 2⁸ = 9990767 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9991027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 237861 + ... + 237902.

It is an arithmetic number, because the mean of its divisors is an integer number (1903056).

Almost surely, 2^9991023 is an apocalyptic number.

9991023 is a deficient number, since it is larger than the sum of its proper divisors (5233425).

9991023 is a wasteful number, since it uses less digits than its factorization.

9991023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475773.

The product of its (nonzero) digits is 4374, while the sum is 33.

The square root of 9991023 is about 3160.8579531513. The cubic root of 9991023 is about 215.3789818353.

The spelling of 9991023 in words is "nine million, nine hundred ninety-one thousand, twenty-three".